Think before you ink? Tattoos as a novel risk factor for immunologic disease

Research problem and specific questionsWe have just shown that tattoos increase the risk of lymphoma – cancer originating from immune cells. Now, it is paramount to invesigate if tattoos also increase the risk of other diseases of the immune system. The tattoo trend has skyrocketed and more than 40% of the Swedish population younger than 40-years is tattooed.

The high prevalence has raised safety concerns but the state-of-knowledge is extremely weak.

Hazardous chemicals in tattoo ink are a pertinent public health threat and authorities including the European Commission have stressed the urgent need for epidemiologic studies.During the tattooing process, large amounts of color pigment are injected into the skin. A fraction remains there while the immune system removes the rest.

This causes systemic translocation of pigments with permanent deposition in lymph nodes. Lymph nodes play a critical role for normal immune functioning.

Toxic chemicals can disrupt regulatory processes of the immune system and cause disease through foreign-body reactions, autoimmunity and hypersensitzation.

Tattoo pigments are industrial chemicals developed for use in car paint and printing ink and have not undergone risk assessment regarding injection into the body.Data and methodThe research group has established the Swedish Tattoo and Body Modifications cohort (TABOO), a globally unique cohort of 13,003 individuals with known tattoo status.

Information on exposure and confounders was collected via a national questionnaire survey in 2021. The response rate was 51 % and 2,622 of the partcipants are tattooed. We will link the cohort to outcome data from the National Patient- and Prescribed Drug Registers.

We will estimate relative risks using robust Cox regression and explore if there is a threshold above which the area of tattooed body surface becomes a health threat.Societal relevance and utilizationThe results are necessary to protect public health through scientifically based riskassesments and information to the healthcare system that tattoos may be a risk factor for severe immunologic disease.

It is also about providing knowledge to the general public to allow individuals to make informed decisions regarding tattoos.Plan for project realisationThe project is conducted in collaboration with the Swedish Medical Products Agency, the healthcare sector and the general public. The project runs over 3-years and we primarily apply for salary costs for the project leader and a posdoc.